The invention relates to improvements in mechanisms for separating water from fine granular material such as are known as oscillating centrifuges, and more particularly to an oscillating centrifuge which has a rotating conically shaped porous sieve cage which is elastically connected with a rotary and an oscillating drive and having a stationary enclosing housing for the collection of water and a housing for the collection of dehydrated solids carried on the sieve cages.
Devices have heretofore been provided for the separating of water from granular materials such as, for example, wet bituminous coal having a granular diameter on the order of zero to 10mm, and one type of device is shown in U.S. Pat. of Heckmann No. 2,886,179. In another device providing a known oscillating centrifuge, as shown in German Pat. No. 1,060,796, the conical sieve cage which is provided rotates and carries out simultaneous rapid axial oscillations. The tapered or small diameter of the frusto conical or truncated cone shaped sieve cage lies beneath the centrifuge. The material to be dewatered is supplied centrally from above, for example, such as wet coal, and is accelerated into a cone arranged within the sieve cage which is widened downwardly and is centrifuged off from the lower rim of a preacceleration cone on the lower end of the sieve cage. From there the centrifuging material migrates during its dehydration upwardly along the sieve cage sleeve widening upwardly conically. Around the cage is a stationary nonrotating filtrate collection container or water collection container respectively. From the upper sieve cage rim, the dehydrated solid is centrifuged off and it must be centrifuged off in a radial direction out over the filtrate collection container and collected on the periphery. Thereafter in the structure of a known type of centrifuge referred to above, a further stationary housing must be located around the stationary filtrate collection container which collects the dehydrated solid centrifuged off from the sieve cage and guides it downwardly.
By virtue of the necessarily large radius of the centrifuged off dehydrated solids, the structure of the heretofore known centrifuge becomes very wide in diameter. This is very disadvantageous, and when the centrifuged off dewatered material, by means of devices arranged beneath the centrifuge, such as chutes or cones, must again be conducted from the periphery to the center in order to be continually conveyed off on a conveyor belt, the structural height of the entire centrifugal installation becomes very large. For example, in the case of coal dewatering as used in modern installations, the coal must be conveyed off over conveyor belts or chain conveyors. For this arrangement known constructions of vertically oscillating centrifuges have proved disadvantageous and have been replaced by a horizontal oscillating centrifuge which has appreciable disadvantages as contrasted with an equivalent vertical oscillating centrifuge, with one of the disadvantages being a substantially smaller output.
An important object of the invention is to construct a vertical oscillating centrifuge having a high capacity output wherein the diameter of the housing for the collection of the dewatered solids and the structural height of the entire centrifugal installation including the mechanism for withdrawal of solids, is as small as possible.
One of the aforementioned problems of oscillating centrifuges of the type heretofore known is obviated in that with the present invention, the conically shaped sieve cage is flared outwardly in a downward direction, and a solids collection housing is provided which extends downwardly at the lower end of the sieve cage where it has the largest diameter.
In the construction of an oscillating centrifuge in accordance with the present invention, the cne tip of the sieve cage lies above the centrifuge, and the dewatered solids are not centrifuged off the upper, but instead over the lower sieve cage rim. Therefore, the radius of the centrifuged off solids does not extend in a radial direction over the filtrate collection container, and it is sufficient if the diameter for the centrifuged solids as they are collected corresponds approximately to the greatest sieve cage diameter. The solids collection housing extending downwardly and being attached to the lower sieve cage end needs only have an internal diameter which is only slightly larger than the diameter of the sieve cage. A solids collection housing concentrically surrounding the filtrate collection container of the type which makes known vertical oscillating centrifuges so wide is not necessary in accordance with the principles of the present invention.
Therefore, the centrifuge construction in accordance with the present invention has a relatively small outer diameter. Also, a comparably small structural height results when the structure is provided to again convey together the centrifuged dewatered solids through chutes or cones on the lower side of the centrifuge from the periphery to the center which is necessary, for example, for charging onto a conveyor belt. Therefore, the vertical oscillating centrifuge in accordance with the present invention when compared wth an equivalent horizontal oscillating centrifuge, has an output rate of approximately 11/2 times the horizontal centrifuge and is particularly well adapted for installation into modern coal dewatering installations.
In accordance with the special features of the invention, the sieve cage is not constructed with its small diameter but instead with its largest diameter connected to the rotary and oscillating drive. By means of this type of construction, the strength of the sieve cage itself is increased, and this construction insures higher axial accelerations of the sieve cage.
An overall objective of the invention is to provide an improved rotating oscillating centrifuge for dewatering material wherein the construction accommodates balancing of drive forces in such a manner that forces are at a minimum so that the overall strength of the construction may be maintained at a minimum and thus decreasing the overall size and the cost of construction and operation of the unit.
Other objects, advantages and features will become more apparent, as will equivalent constructions which are intended to be covered herein from the teaching of the principles of the invention in connection with the disclosure of the preferred embodiment in the specification, claims and drawings, in which: